[ENHANCEMENT] Improve build script logging

[youngcoder45]

Problem / motivation

Enhance build script output to provide better feedback.
Users may not understand what is happening during ISO build.

Proposed solution

1. Add echo/log statements
2. Show progress (start/end steps)
3. Add error messages

Alternatives considered

• Clear logs during build
• Errors are understandable
  Files:
• scripts/build-iso.sh